1. Field of the Invention
The present invention relates to electromagnetically shielded electrical connectors, and more particularly to an electrical connector having a conductive shield which is fully insulated from being contacted by a user of the connector and also fully shields the electrical contacts of the connector with respect to electromagnetic interference.
2. Description of the Prior Art
Shielded electrical connectors provide a means for both shielding electrical connections from external electromagnetic signals and preventing the systems which use the connectors from emitting electromagnetic signals. The connectors generally accomplish this goal by providing a means which continues the shielding of a shielded cable either to another shielded cable or to an electronic device. Shielded electrical connectors are typically found in telecommunications and computer applications, and furthermore are increasingly being used in patient monitoring situations, such as within a hospital or operating room, due to the proliferation of electronic devices in these environments which emit electromagnetic interference, such as a portable cellular telephone, electrosurgical instrumentation, defibrillators, etc.
Furthermore, high frequency electromagnetic signals are susceptible to interference from other undesirable electromagnetic signals. In addition, these signals also naturally generate unwanted electromagnetic signals of their own which may interfere with other electronic devices. Thus, the use and transmission of high frequency electrical signals, as well as the shielding for preventing high frequency electrical signals from contaminating desired signals, establishes the need for shielded electrical connections. Still furthermore, electromagnetic shielding is generally required to satisfy a relevant government standard which places limits on the emission of interfering electromagnetic signals, such as the United States Federal Communications Commission for telecommunications applications and the United States Food and Drug Administration for patient monitoring equipment. The use of a grounded continuous metal shield which surrounds the electrical wiring, cable or electronic device is an effective way to minimize these undesirable effects and satisfies most applicable standards. Finally, shielded electrical connectors are necessary to maintain the integrity of a shielded system from one device to another device.
Electrical connectors are known in the art which generally comprise an insulative or dielectric housing which contains a plurality of terminals and a like plurality of terminal passages. In addition, a pair of metal shell members are fixed to the outside of the insulative housing to form a electromagnetic shield for the connector. Although such electromagnetic shields may be sufficient for use in some environments, in the patient monitoring environment an exposed shield would be extremely undesirable, as well as not meeting applicable safety standards, since it can be contacted by the patient or hospital care provider and thereby possibly transfer a dangerous electrical shock. Conductive shields for connectors are also known in the prior art which reside along an inside surface of the electrical connector, and therefore are not exposed on the outside thereof where they can be contacted by the patient or hospital care provider. However, these known prior art insulated shields are not known to have provided for a continuous electromagnetic shielding of the electrical contacts inside the connector. That is, it is necessary that the electrical connections provided by the electrical contacts be fully shielded across their connection to a mating connector in order to prevent electromagnetic interference from "seeping in" through gaps in the electromagnetic shield which occur between one electrical connector and another, and thereby contaminate the signals being carried by the signal conductors connected to the electrical contacts. Additionally, a fully shielded connector will prevent a "seeping out" of a portion of the electrical signals being carried by the connector.
It is an object of the present invention to provide an electrical connector with a conductive shield which fully shields the electrical contacts of the electrical connector along their length and which mates with and continues the shield of a mating electrical connector, so that the electrical connections made by the connector are fully shielded across the connection.
Additionally, it is necessary in some situations that the conductive shield be completely insulated from being contacted by a user of the electrical connector.
It is a further object of the invention to provide a fully shielded, fully insulated electrical connector which can be manufactured in a manner which is simple and inexpensive.